Question

Describe how you would separate a mixture of water, sand and iron metal filings. Which separation techniques would you use?

Answer 1

Hint: We can perform this in two ways: either by removing water from the mixture and later on deal with the sand and iron filling mixture or we can first remove the iron fillings by magnetic separation or reaction in aqueous medium and later on deal with the mixture of sand and water.

Complete step-by-step answer: There are many processes by which we can separate iron filings and water from the sand so as to use it again. The processes are given below:-
-First we can try to remove iron filings from the mixture as follows:-
(A) We can use the magnetic separation method to collect all the iron fillings as iron has a ferromagnetic nature due to which it will easily get attracted and will separate out. We can cover the magnet with cotton and put it inside the mixture so that all the iron fillings get attracted and stuck in the cotton piece.
(B) Similarly we can start swirling the mixture and put a magnet at the bottom so that when the mixture gets rotated, the iron fillings are stuck at the bottom of the container.
-Now, we can try to remove water from the sand:-
(A) Sedimentation and decantation: The mixture is kept undisturbed for some time. After some time, sand being heavier and insoluble in water, gets settled down at the bottom of the container. Now, water is poured into another container or beaker to separate it from sand but do this process carefully.
(B) Filtration: The mixture of sand and water is passed through a filter paper (a filter paper is paper with very fine pore that allows only a particular range of molecules to pass). Sand particles being larger in size are retained by the filter paper and get separated from water at the end.
 This way we can easily separate a mixture of water, sand and iron metal fillings.

Note: -We can prefer to use magnetic separation method for all the metals which have ferromagnetic properties because they will be easily attracted to the magnet.
-Also we can perform filtration method in the beginning and then use magnetic separation method when the mixture of sand and iron filings gets dried.